The present invention relates to an automobile air conditioning system having the function of temperature control of the air in the automobile compartment.
In automobiles including the passenger car having a small riding space or compartment, the value of the comfortable temperature required around each seat (air-conditioning zone) or the actual temperature is known to be greatly different depending on the propensity of the passengers (including the driver) or the effect of sunlight. Systems have so far been proposed for changing the air-conditioning effect on each seat independently or making effects uneven the effect on one seat from the effect on another.
One of the simplest examples of such a system comprises an air-conditioning unit, a plurality of air outlets facing respective sections of the compartment, ventilation ducts for conducting the air conditioned in the air-conditioning unit to the air outlets, and a distribution valves arranged in the ventilation ducts for making the distribution of the air uneven to the respective sections of the compartment from the air outlets. Although the magnitude of the air flow rate at each section of the compartment causes the difference of temperature of the respective sections, the air-conditioning feeling of the passengers including driver also depends on the air flow rate, and therefore it is not desirable to make the air flow rate uneven to a large measure. It is thus difficult to attain a uniform temperature of the respective sections or a sufficiently large temperature difference among the sections. This is also the case when an electrically-operated air blower instead of the distribution valve is provided at each air outlet so that the air conduction ability of the blower is adjusted appropriately or when a blowing direction adjusting fin is provided at each air outlet so that the angle of the fin is changed. In both cases, it is difficult to control the temperature satisfactorily without adversely affecting the air conditioning feeling of the passengers.
In other known methods, instead of changing the distribution of the air flow rate, a temperature control unit is provided for each section of the compartment. The most well known example is what is called a dual air-conditioning system comprising a main air conditioning unit arranged on the front part of the compartment for air-conditioning the front seat section mainly and a rear air-conditioning unit arranged at the rear part of the compartment for air-conditioning the rear seat section of the compartment mainly. In the case where three or more sections of the compartment are to be temperature-controlled independently such as when the front or rear seat section is subdivided into right and left seat sections, the aforementioned method of changing the air flow rate is required to be used at the same time, thus making a satisfactory temperature control impossible.
Still another example such as disclosed in Japanese Patent Laid-Open Publication No. 2213/81 suggests a method in which the compartment is divided into a plurality of air-conditioning zones corresponding to seats and each air-conditioning zone is provided with an independent air outlet and an independent temperature control system. In this method, the temperature of the air blown out to each air-conditioning zone from a corresponding air outlet is controlled to a desired value more easily than in the aforementioned methods by regulating the temperature control system for each air-conditioning zone. An ordinary passenger car is generally capable of accommodating about four passengers and therefore is required to be divided into four air-conditioning zones. This requires the air-conditioning unit to be provided with four temperature control systems as many as the air-conditioning zones, thereby structurally complicating and unduly increasing the size of the temperature control systems and the dusts. Further, an air duct is required for each temperature control system leading to each air outlet, resulting in an increased ventilation resistance.